Cartridges for preparing a liquid product, such as, for example, a beverage, by introducing into the cartridge liquid (possibly under pressure and/or at high temperature) and/or steam constitute a technological sector that is extremely rich and articulated, as documented, for example, by FR-A-757 358, FR-A-2 373 999 (to which U.S. Pat. No. 4,136,202 corresponds), FR-A-2 556 323, GB-A-938 617, GB-A-2 023 086, CH-A-406 561, U.S. Pat. No. 3,403,617, U.S. Pat. No. 3,470,812, U.S. Pat. No. 3,607,297 (to which FR-A-1 537 031 corresponds), WO-A-86/02 537, EP-A-0 199 953, EP-A-0 211 511, EP-A-0 242 556, EP-A-0 468 078, EP-A-0 469 162 and EP-A-0 507 905.
A fair part of the solutions described in the documents referred to above primarily regards the preparation of liquid products constituted by beverages such as coffee, tea, chocolate, broth, soups, or various infusions. As regards the preparation of coffee, known (for example from EP-A-0 507 905, already mentioned previously) are solutions designed to enable the preparation of espresso coffee.
In particular, known in the production of the present applicant are cartridges sold under the trade name Espresso Family, taken as model for the preamble of Claim 1. These are cartridges containing a dose of at least one substance (for example, powdered coffee) enclosed between two foils that can be traversed by liquid and/or steam with the two foils connected together around the aforesaid dose.